U.S. patent number 8,440,756 [Application Number 13/395,541] was granted by the patent office on 2013-05-14 for flame-retardant polyamide resin composition.
This patent grant is currently assigned to Mitsubishi Gas Chemical Company, Inc.. The grantee listed for this patent is Shinichi Ayuba, Kentaro Ishii, Hisayuki Kuwahara, Shun Ogawa, Takahiko Sumino. Invention is credited to Shinichi Ayuba, Kentaro Ishii, Hisayuki Kuwahara, Shun Ogawa, Takahiko Sumino.
United States Patent |
8,440,756 |
Ishii , et al. |
May 14, 2013 |
Flame-retardant polyamide resin composition
Abstract
Disclosed is a flame-retardant polyamide resin composition,
including: a polyamide (A) containing a diamine unit including 70
mol % or more of a p-xylylenediamine unit and a dicarboxylic acid
unit including 70 mol % or more of a linear aliphatic dicarboxylic
acid unit having 6 to 18 carbon atoms; an organic halogen compound
(B) that serves as a flame retardant; an inorganic compound (C)
that serves as a flame retardant aid; and an inorganic filler (D),
in which the polyamide (A) includes a polyamide having a phosphorus
atom concentration of 50 to 1,000 ppm and a YI value of 10 or less
in a color difference test in accordance with JIS-K-7105, and a
content of the organic halogen compound (B), a content of the
inorganic compound (C), and a content of the inorganic filler (D)
are 1 to 100 parts by mass, 0.5 to 50 parts by mass, and 0 to 100
parts by mass, respectively, with respect to 100 parts by mass of
the polyamide (A).
Inventors: |
Ishii; Kentaro (Kanagawa,
JP), Kuwahara; Hisayuki (Kanagawa, JP),
Ogawa; Shun (Kanagawa, JP), Ayuba; Shinichi
(Kanagawa, JP), Sumino; Takahiko (Kanagawa,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Ishii; Kentaro
Kuwahara; Hisayuki
Ogawa; Shun
Ayuba; Shinichi
Sumino; Takahiko |
Kanagawa
Kanagawa
Kanagawa
Kanagawa
Kanagawa |
N/A
N/A
N/A
N/A
N/A |
JP
JP
JP
JP
JP |
|
|
Assignee: |
Mitsubishi Gas Chemical Company,
Inc. (Tokyo, JP)
|
Family
ID: |
43732572 |
Appl.
No.: |
13/395,541 |
Filed: |
September 14, 2010 |
PCT
Filed: |
September 14, 2010 |
PCT No.: |
PCT/JP2010/065879 |
371(c)(1),(2),(4) Date: |
March 12, 2012 |
PCT
Pub. No.: |
WO2011/030911 |
PCT
Pub. Date: |
March 17, 2011 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20120172512 A1 |
Jul 5, 2012 |
|
Foreign Application Priority Data
|
|
|
|
|
Sep 14, 2009 [JP] |
|
|
2009-211834 |
|
Current U.S.
Class: |
524/469; 524/470;
524/464 |
Current CPC
Class: |
C08L
25/18 (20130101); C08L 77/06 (20130101); C08L
25/18 (20130101); C08L 77/06 (20130101); C08K
3/2279 (20130101) |
Current International
Class: |
C08K
5/03 (20060101) |
Field of
Search: |
;524/464,469,470 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
1898331 |
|
Jul 2007 |
|
CN |
|
2 025 718 |
|
Feb 2009 |
|
EP |
|
47 15106 |
|
May 1972 |
|
JP |
|
49 35358 |
|
Sep 1974 |
|
JP |
|
5 117524 |
|
May 1993 |
|
JP |
|
5 170897 |
|
Jul 1993 |
|
JP |
|
6 192416 |
|
Jul 1994 |
|
JP |
|
2000 204240 |
|
Jul 2000 |
|
JP |
|
2004 131544 |
|
Apr 2004 |
|
JP |
|
2007 291250 |
|
Nov 2007 |
|
JP |
|
2008 214526 |
|
Sep 2008 |
|
JP |
|
2008 280535 |
|
Nov 2008 |
|
JP |
|
2009 035656 |
|
Feb 2009 |
|
JP |
|
2009 161748 |
|
Jul 2009 |
|
JP |
|
200909477 |
|
Jul 1997 |
|
TW |
|
2008 053911 |
|
May 2008 |
|
WO |
|
Other References
International Search Report Issued Dec. 7, 2010 in PCT/JP10/65879
Filed Sep. 14, 2010. cited by applicant .
U.S. Appl. No. 13/395,535, filed Mar. 12, 2012, Ogawa, et al. cited
by applicant .
U.S. Appl. No. 13/391,075, filed Feb. 17, 2012, Ishii, et al. cited
by applicant .
Office Action issued Feb. 4, 2013, Chineese Patent Application No.
201080040962. cited by applicant .
European Search Report issued Feb. 4, 2013 in PCT/JP2010065879.
cited by applicant.
|
Primary Examiner: Szekely; Peter
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier
& Neustadt, L.L.P.
Claims
The invention claimed is:
1. A flame-retardant polyamide resin composition, comprising: a
polyamide (A) comprising a diamine unit comprising 70 mol % or more
of a p-xylylenediamine unit, a dicarboxylic acid unit comprising 70
mol % or more of a linear aliphatic dicarboxylic acid unit
comprising 6 to 18 carbon atoms, and a phosphorous atom
concentration of 50 to 1,000 ppm; 1 to 100 parts by mass of an
organic halogen compound (B), based on 100 parts by mass of the
polyamide (A); 0.5 to 50 parts by mass an inorganic compound (C),
based on 100 parts by mass of the polyamide (A); and 0 to 100 parts
by mass an inorganic filler (D), based on 100 parts by mass of the
polyamide (A), wherein the polyamide (A) has a YI value of 10 or
less in a color difference test in accordance with JIS-K-7105.
2. The composition of claim 1, wherein the linear aliphatic
dicarboxylic acid unit comprises at least one selected from the
group consisting of an azelaic acid unit, a sebacic acid unit, an
undecanedioic acid unit, and a dodecanedioic acid unit.
3. The composition of claim 1, wherein the linear aliphatic
dicarboxylic acid unit comprises at least one selected from the
group consisting of a sebacic acid unit and an azelaic acid
unit.
4. The composition of claims of claim 1, wherein the polyamide (A)
comprises a diamine unit comprising 90 mol % or more of a
p-xylylenediamine unit and a dicarboxylic acid unit comprising 90
mol % or more of at least one selected from the group consisting of
a sebacic acid unit and an azelaic acid unit.
5. The composition of claim 1, wherein the polyamide (A) has a
relative viscosity within a range of from 1.8 to 4.2.
6. The composition of claim 1, wherein the polyamide (A) has a
number average molecular weight (Mn) within a range of from 10,000
to 50,000 in gel permeation chromatography, and a dispersivity
(weight average molecular weight/number average molecular
weight=Mw/Mn) within a range of from 1.5 to 5.0.
7. The composition of claim 1, wherein the organic halogen compound
(B) comprises at least one selected from the group consisting of
brominated polystyrene, brominated polyphenylene ether, brominated
polycarbonate, a brominated bisphenol-type epoxy-based polymer, a
brominated styrene maleic anhydride polymer, a brominated epoxy
resin, a brominated phenoxy resin, decabromodiphenyl ether,
decabromobiphenyl, a brominated crosslinked aromatic polymer, and
perchlorocyclopentadecane.
8. The composition of claim 1, wherein the organic halogen compound
(B) comprises at least one selected from the group consisting of
brominated polystyrene and brominated polyphenylene ether.
9. The composition of claim 1, wherein the organic halogen compound
(B) has a halogen atom content of 15 to 87% by mass.
10. The composition of claim 1, wherein the inorganic compound (C)
comprises at least one selected from the group consisting of
antimony trioxide, antimony pentoxide, sodium antimonate, tin
oxide, iron oxide, zinc oxide, zinc borate, magnesium hydroxide,
calcium hydroxide, calcium carbonate, and kaolin clay.
11. The composition of claim 1, wherein the inorganic compound (C)
comprises at least one selected from the group consisting of
antimony trioxide, antimony pentoxide, and sodium antimonate.
12. The composition of claim 1, wherein the inorganic filler (D)
comprises at least one selected from the group consisting of a
glass fiber, a glass bead, a carbon fiber, a boron fiber, talc,
mica, silica, silica alumina, alumina, graphite, kaolin, titanium
dioxide, and molybdenum disulfide.
13. The composition of claim 1, wherein the inorganic filler (D)
comprises at least one selected from the group consisting of a
glass fiber and a carbon fiber.
14. A molded article, comprising: the composition of claim 1.
15. The molded article claim 14, which is an electrical part or an
electronic part.
16. The composition of claim 1, the polyamide (A) has a phosphorus
atom concentration of 50 to 400 ppm and a YI value of 6 or less in
a color difference test in accordance with JIS-K-7105.
17. The composition of claim 1, wherein the linear aliphatic
dicarboxylic acid unit comprises a sebacic acid unit.
18. The composition of claim 1, wherein the linear aliphatic
dicarboxylic acid unit comprises an azelaic acid unit.
19. The composition of claim 1, wherein the organic halogen
compound (B) comprises brominated polystyrene.
20. The composition of claim 1, wherein the organic halogen
compound (B) comprises brominated polyphenylene ether.
Description
TECHNICAL FIELD
The present invention relates to a flame-retardant polyamide resin
composition, and more specifically, to a flame-retardant polyamide
resin composition including: a polyamide resin containing a
p-xylylenediamine unit and a linear aliphatic dicarboxylic acid
unit having 6 to 18 carbon atoms as major components; and a
specific amount of an additive.
BACKGROUND ART
An aliphatic polyamide typified by nylon 6 or nylon 66 has
excellent properties such as heat resistance, chemical resistance,
rigidity, abrasion resistance, and moldability, and hence is used
for a variety of applications as an engineering plastic. In
electrical and electronic fields, the aliphatic polyamide is
required to have high flame retardance based on a UL94 standard,
and hence many methods of imparting flame retardance using a
variety of flame retardants have been proposed and put to practical
use. However, such aliphatic polyamide has high water
absorbability, and hence there causes a problem in that a molded
article produced from the polyamide changes in dimension and
reduces in its physical properties. Further, in recent years, in
the electrical and electronic fields which require imparting of
flame retardance, a method called surface mount technology (SMT)
has been rapidly spread for the purposes of high-density mounting
of parts, promotion of the efficiency of a soldering step, and the
like. Therefore, the conventional resin has become ineffective in
terms of heat resistance as well.
Meanwhile, recently, a semi-aromatic polyamide which contains, as a
major component, a polyamide formed of 1,6-hexanediamine and
terephthalic acid and is called 6T polyamide has also been used in
the electrical and electronic fields which require flame
retardance. For example, Patent Documents 1 and 2 each propose a
technology for imparting flame retardance to a semi-aromatic
polyamide such as the 6T polyamide.
However, the polyamide formed of 1,6-hexanediamine and terephthalic
acid has a melting point of about 370.degree. C., and hence cannot
be used actually because melt polymerization and melt molding need
to be carried out at a temperature equal to or higher than a
polymer degradation temperature. Therefore, in actual use, adipic
acid, isophthalic acid, .epsilon.-caprolactam, or the like is
copolymerized at about 30 to 40 mol % to prepare a polyamide having
a composition to achieve a melting point as low as about
320.degree. C. which falls within a temperature range that enables
actual use of the polyamide. Such copolymerization of a third
component or a fourth component is effective for lowering the
melting point, but may lead to lowering of a crystallization rate
and a final crystallization degree. As a result, not only physical
properties such as rigidity, chemical resistance, and dimensional
stability at high temperature are lowered, but also productivity
may be lowered due to elongation of a molding cycle. Further,
changes in physical properties such as dimensional stability caused
by water absorption are modestly improved through the introduction
of an aromatic group compared to the conventional polyamide, but
the problem has not been solved actually.
CITATION LIST
Patent Literature
[Patent Document 1] JP 3-239755 A
[Patent Document 2] JP 4-96970 A
SUMMARY OF INVENTION
Technical Problem
A problem to be solved by the present invention is to provide a
flame-retardant polyamide resin composition excellent in physical
properties such as moldability, mechanical properties, heat
resistance, and low water absorbability.
Solution to Problem
The inventors of the present invention have made intensive studies.
As a result, the inventors have found out that a flame-retardant
polyamide resin composition excellent in the above-mentioned
performances can be obtained by blending specific amounts of a
flame retardant, a flame retardant aid, and a reinforcement in a
polyamide formed of a diamine component containing
p-xylylenediamine as a major component and a dicarboxylic acid
component containing a linear aliphatic dicarboxylic acid having 6
to 18 carbon atoms as a major component, and thus attained the
present invention.
The present invention relates to the following items [1] and
[2].
[1] A flame-retardant polyamide resin composition, comprising: a
polyamide (A) containing a diamine unit including 70 mol % or more
of a p-xylylenediamine unit and a dicarboxylic acid unit including
70 mol % or more of a linear aliphatic dicarboxylic acid unit
having 6 to 18 carbon atoms; an organic halogen compound (B) that
serves as a flame retardant; an inorganic compound (C) that serves
as a flame retardant aid; and an inorganic filler (D), wherein the
polyamide (A) comprises a polyamide having a phosphorus atom
concentration of 50 to 1,000 ppm and a YI value of 10 or less in a
color difference test in accordance with JIS-K-7105, and a content
of the organic halogen compound (B), a content of the inorganic
compound (C), and a content of the inorganic filler (D) are 1 to
100 parts by mass, 0.5 to 50 parts by mass, and 0 to 100 parts by
mass, respectively, with respect to 100 parts by mass of the
polyamide (A).
[2] A molded article, comprising the flame-retardant polyamide
resin composition according to the item [1].
Advantageous Effects of Invention
The flame-retardant polyamide resin composition of the present
invention is excellent not only in flame retardance but also in a
variety of physical properties such as moldability, mechanical
properties, heat resistance, and low water absorbability, and can
be suitably used in a wide range of applications and conditions as
a molding material for a variety of industries and industrial and
household products such as electrical and electronic parts,
automotive parts, and mechanical parts required to have flame
retardance.
DESCRIPTION OF EMBODIMENTS
A flame-retardant polyamide resin composition of the present
invention includes, as mentioned below, a polyamide (A) containing
a diamine unit and a dicarboxylic acid unit, an organic halogen
compound (B) that serves as a flame retardant, and an inorganic
compound (C) that serves as a flame retardant aid, and as required,
further includes an inorganic filler (D) that serves as a
reinforcement. Herein, the diamine unit refers to a constituent
unit derived from a raw material diamine component, and the
dicarboxylic acid unit refers to a constituent unit derived from a
raw material dicarboxylic acid component.
<Polyamide (A)>
The polyamide (A) contains the diamine unit including 70 mol % or
more of a p-xylylenediamine unit and the dicarboxylic acid unit
including 70 mol % or more of a linear aliphatic dicarboxylic acid
unit having 6 to 18 carbon atoms.
The p-xylylenediamine unit in the diamine unit is contained at a
concentration of preferably 80 mol % or more, more preferably 90
mol % or more, most preferably 100 mol %. The linear aliphatic
dicarboxylic acid unit having 6 to 18 carbon atoms in the
dicarboxylic acid unit is contained at a concentration of
preferably 80 mol % or more, more preferably 90 mol % or more, most
preferably 100 mol %.
The polyamide (A) can be obtained by polycondensation of a diamine
component including 70 mol % or more of p-xylylenediamine and a
dicarboxylic acid component including 70 mol % or more of a linear
aliphatic dicarboxylic acid having 6 to 18 carbon atoms.
The diamine component as a raw material of the polyamide (A)
includes p-xylylenediamine at a concentration of 70 mol % or more,
preferably 80 mol % or more, more preferably 90 mol % or more,
particularly preferably 100 mol %. When the concentration of the
p-xylylenediamine in the diamine component is adjusted to 70 mol %
or more, a polyamide to be obtained exhibits a high melting point
and high crystallinity and can be suitably used for a variety of
applications as a polyamide being excellent in heat resistance,
chemical resistance, and the like and having low water
absorbability. If the concentration of p-xylylenediamine in the
diamine component used as a raw material is less than 70 mol %, the
polyamide to be obtained has lowered heat resistance and chemical
resistance and increased water absorbability.
A raw material diamine component other than p-xylylenediamine may
be exemplified by, but not limited to, an aliphatic diamine such as
1,4-butanediamine, 1,6-hexanediamine, 1,8-octanediamine,
1,10-decanediamine, 1,12-dodecanediamine,
2-methyl-1,5-pentanediamine, 2,2,4-trimethyl-1,6-hexanediamine,
2,4,4-trimethyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine, or
5-methyl-1,9-nonanediamine, an alicyclic diamine such as
1,3-bis(aminomethyl)cyclohexane, 1,4-bis (aminomethyl)cyclohexane,
cyclohexanediamine, methylcyclohexanediamine, or isophoronediamine,
an aromatic diamine such as m-xylylenediamine, or a mixture
thereof.
The dicarboxylic acid component as a raw material of the polyamide
(A) includes the linear aliphatic dicarboxylic acid having 6 to 18
carbon atoms at a concentration of 70 mol % or more, preferably 80
mol % or more, more preferably 90 mol % or more, particularly
preferably 100 mol %. When the concentration of the linear
aliphatic dicarboxylic acid having 6 to 18 carbon atoms is adjusted
to 70 mol % or more, a polyamide to be obtained exhibits fluidity
in melt processing, high crystallinity, and low water absorption
and can be suitably used for a variety of applications as a
polyamide excellent in heat resistance, chemical resistance,
molding processability, and dimensional stability. If the
concentration of the linear aliphatic dicarboxylic acid having 6 to
18 carbon atoms in the dicarboxylic acid component used as a raw
material is less than 70 mol %, the polyamide to be obtained has
lowered heat resistance, chemical resistance, and molding
processability.
Examples of the linear aliphatic dicarboxylic acid having 6 to 18
carbon atoms may include adipic acid, pimelic acid, suberic acid,
azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid,
tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid,
and hexadecanedioic acid. Of those, preferred is at least one
selected from the group consisting of azelaic acid, sebacic acid,
undecanedioic acid, and dodecanedioic acid, and particularly
preferred are sebacic acid and/or azelaic acid. In the case where
an aliphatic dicarboxylic acid having 5 or less carbon atoms is
used, the dicarboxylic acid has a low melting point and a low
boiling point, and hence is distilled out from the reaction system
during polycondensation reactions to change a reaction molar ratio
between the diamine and the dicarboxylic acid, resulting in low
mechanical properties and thermal stability of a polyamide to be
obtained. Meanwhile, in the case where an aliphatic dicarboxylic
acid having 19 or more carbon atoms is used, the heat resistance
cannot be obtained because the melting point of the polyamide is
significantly lowered.
A raw material dicarboxylic acid other than the linear aliphatic
dicarboxylic acid having 6 to 18 carbon atoms may be exemplified
by, but not limited to, malonic acid, succinic acid, 2-methyladipic
acid, trimethyladipic acid, 2,2-dimethylglutaric acid,
2,4-dimethylglutaric acid, 3,3-dimethylglutaric acid,
3,3-diethylsuccinic acid, 1,3-cyclopentanedicarboxylic acid,
1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid,
isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic
acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic
acid, 2,7-naphthalenedicarboxylic acid, or a mixture thereof.
A lactam such as .epsilon.-caprolactam or laurolactam, or an
aliphatic aminocarboxylic acid such as aminocaproic acid or
aminoundecanoic acid can also be used as a copolymerization
component for constructing the polyamide (A) as well as the diamine
components and the dicarboxylic acid components as long as an
effect of the present invention is not impaired.
A small amount of a monofunctional compound having reactivity with
a terminal amino group or a terminal carboxyl group of the
polyamide may be added as a molecular weight modifier upon the
polycondensation of the polyamide (A). Examples of the compound
which can be used may include, but not limited to, aliphatic
monocarboxylic acids such as acetic acid, propionic acid, butyric
acid, valeric acid, caproic acid, caprylic acid, lauric acid,
tridecylic acid, myristic acid, palmitic acid, stearic acid, and
pivalic acid, aromatic monocarboxylic acids such as benzoic acid,
toluic acid, and naphthalenecarboxylic acid, aliphatic monoamines
such as butylamine, amylamine, isoamylamine, hexylamine,
heptylamine, and octylamine, aromatic-aliphatic monoamines such as
benzylamine and methylbenzylamine, and mixtures thereof.
In the case where a molecular weight modifier is used in
polycondensation of the polyamide (A), a suitable amount of the
molecular weight modifier used varies depending on, for example,
the reactivity and boiling point of the molecular weight modifier
used and reaction conditions, and is usually about 0.1 to 10% by
mass with respect to the total of the diamine component and
dicarboxylic acid component used as raw materials.
A phosphorus atom-containing compound may be added to a system of
polycondensation of the polyamide (A) as an antioxidant for
preventing coloring of the polyamide due to a catalyst for the
polycondensation reaction and oxygen present in the
polycondensation system.
Examples of the phosphorus atom-containing compound include
alkaline earth metal salts of hypophosphorous acid, alkali metal
salts of phosphorous acid, alkaline earth metal salts of
phosphorous acid, alkali metal salts of phosphoric acid, alkaline
earth metal salts of phosphoric acid, alkali metal salts of
pyrophosphoric acid, alkaline earth metal salts of pyrophosphoric
acid, alkali metal salts of metaphosphoric acid, and alkaline earth
metal salts of metaphosphoric acid.
Specific examples thereof may include calcium hypophosphite,
magnesium hypophosphite, sodium phosphite, sodium hydrogen
phosphite, potassium phosphite, potassium hydrogen phosphite,
lithium phosphite, lithium hydrogen phosphite, magnesium phosphite,
magnesium hydrogen phosphite, calcium phosphite, calcium hydrogen
phosphite, sodium phosphate, disodium hydrogen phosphate, sodium
dihydrogen phosphate, potassium phosphate, dipotassium hydrogen
phosphate, potassium dihydrogen phosphate, magnesium phosphate,
dimagnesium hydrogen phosphate, magnesium dihydrogen phosphate,
calcium phosphate, dicalcium hydrogen phosphate, calcium dihydrogen
phosphate, lithium phosphate, dilithium hydrogen phosphate, lithium
dihydrogen phosphate, sodium pyrophosphate, potassium
pyrophosphate, magnesium pyrophosphate, calcium pyrophosphate,
lithium pyrophosphate, sodium metaphosphate, potassium
metaphosphate, magnesium metaphosphate, calcium metaphosphate,
lithium metaphosphate, and mixtures thereof. Of those, preferred
are calcium hypophosphite, magnesium hypophosphite, calcium
phosphite, calcium hydrogen phosphite, and calcium dihydrogen
phosphate, and more preferred is calcium hypophosphite. It should
be noted that each of those phosphorus atom-containing compounds
may be a hydrate.
The amount of the phosphorus atom-containing compound added to the
system of polycondensation of the polyamide (A) is 50 to 1,000 ppm,
preferably 50 to 400 ppm, more preferably 60 to 350 ppm,
particularly preferably 70 to 300 ppm in terms of a phosphorus atom
concentration in the polyamide (A). In the case where the
phosphorus atom concentration in the polyamide (A) is less than 50
ppm, the effect of the compound as the antioxidant is not
sufficient exerted, and the polyamide resin composition is liable
to be colored. Meanwhile, in the case where the phosphorus atom
concentration in the polyamide (A) is more than 1,000 ppm, a
gelation reaction of the polyamide resin composition is promoted,
and foreign matter probably due to the phosphorus atom-containing
compound may be mixed in a molded article, which is liable to
deteriorate the appearance of the molded article.
The phosphorus atom concentration in the polyamide (A) is
preferably derived from at least one kind of phosphorus
atom-containing compound selected from the group consisting of an
alkaline earth metal salt of hypophosphorous acid, an alkali metal
salt of phosphorous acid, an alkaline earth metal salt of
phosphorous acid, an alkali metal salt of phosphoric acid, an
alkaline earth metal salt of phosphoric acid, an alkali metal salt
of pyrophosphoric acid, an alkaline earth metal salt of
pyrophosphoric acid, an alkali metal salt of metaphosphoric acid,
and an alkaline earth metal salt of metaphosphoric acid, more
preferably derived from at least one kind of phosphorus
atom-containing compound selected from the group consisting of
calcium hypophosphite, magnesium hypophosphite, calcium phosphite,
and calcium dihydrogen phosphate.
Further, a polymerization rate modifier is preferably added to the
system of polycondensation of the polyamide (A) in combination with
the phosphorus atom-containing compound. In order to prevent
coloring of the polyamide during polycondensation, it is necessary
that there be a sufficient amount of the phosphorus atom-containing
compound. However, the compound may cause gelation of the
polyamide, and hence in order to control a reaction rate of
amidation as well, the polymerization rate modifier is preferably
used together with the compound.
Examples of the polymerization rate modifier include alkali metal
hydroxides, alkaline earth metal hydroxides, alkali metal acetates,
and alkaline earth metal acetates. Of those, alkali metal
hydroxides and alkali metal acetates are preferred. Examples of the
polymerization rate modifier include lithium hydroxide, sodium
hydroxide, potassium hydroxide, rubidium hydroxide, cesium
hydroxide, magnesium hydroxide, calcium hydroxide, strontium
hydroxide, barium hydroxide, lithium acetate, sodium acetate,
potassium acetate, rubidium acetate, cesium acetate, magnesium
acetate, calcium acetate, strontium acetate, barium acetate, and
mixtures thereof. Of those, preferred are sodium hydroxide,
potassium hydroxide, magnesium hydroxide, calcium hydroxide, sodium
acetate, and potassium acetate, and more preferred are sodium
hydroxide, sodium acetate, and potassium acetate.
In the case where the polymerization rate modifier is added to the
polycondensation system, from the viewpoint of a balance between
promotion and suppression of the amidation reaction, the molar
ratio between a phosphorus atom in the phosphorus atom-containing
compound and the polymerization rate modifier (=[molar number of
polymerization rate modifier]/[molar number of phosphorus atom in
phosphorus atom-containing compound]) is preferably 0.3 to 1.0,
more preferably 0.4 to 0.95, particularly preferably 0.5 to
0.9.
A polymerization method for the polyamide (A) may be an arbitrary
method such as: (a) polycondensation in a molten state; (b)
so-called solid-phase polymerization involving producing a
low-molecular-weight polyamide by polycondensation in a molten
state and heat-treating the resultant polyamide in a solid-phase
state; or (c) extrusion polymerization involving producing a
low-molecular-weight polyamide by polycondensation in a molten
state and increasing the molecular weight in a molten state using a
kneading extruder.
The method for polycondensation in a molten state is not
particularly limited, and examples thereof may include: a method
involving conducting polycondensation in a molten state while
removing water and condensation water by heating an aqueous
solution of a nylon salt of a diamine component and a dicarboxylic
acid component under increased pressure; and a method involving
conducting polycondensation at ordinary pressure or in a
pressurized steam atmosphere by directly adding a diamine component
to a dicarboxylic acid in a molten state. In the case where
polymerization is carried out by directly adding a diamine to a
dicarboxylic acid in a molten state, polycondensation is carried
out while controlling the reaction temperature so that the
temperature is not lower than the melting points of an oligoamide
and a polyamide to be generated by continuously adding the diamine
component to a molten dicarboxylic acid phase to keep the reaction
system to a uniform liquid state. In the case where, in production
of a product by the above-mentioned polycondensation method, the
inside of a device is washed because of, for example, a change in
the type of the product, triethylene glycol, ethylene glycol,
m-xylylenediamine, or the like may be used.
The polyamide obtained by melt polycondensation is taken out first,
pelletized, and then dried before use. The polyamide may be
produced by solid-phase polymerization to further increase a
polymerization degree. As a heating device to be used for drying or
solid-phase polymerization, a continuous heat drying device, a
rotary drum heating device called tumble dryer, conical dryer, or
rotary dryer, and a cone-shaped heating device equipped with a
blade on its inside, called nautamixer are suitably used. However,
the device is not limited thereto, and a known method and device
may be used. In particular, in the case of conducting solid-phase
polymerization of the polyamide, of the above-mentioned devices, a
rotary drum heating device is preferably used because the system
can be sealed to facilitate polycondensation in a state in which
oxygen, which causes coloring, is removed.
The polyamide (A) is less colored and less gelatinized. Further,
the polyamide (A) has a YI value of 10 or less, preferably 6 or
less, more preferably 5 or less, still more preferably 1 or less,
in a color difference test in accordance with JIS-K-7105. A molded
article obtained from a resin composition containing a polyamide
(A) having a YI value of more than 10 is not preferred because the
article has a yellowish color and hence has low marketability.
Although there are some indices of the polymerization degree of a
polyamide, a relative viscosity is generally used. The relative
viscosity of the polyamide (A) is preferably 1.8 to 4.2, more
preferably 1.9 to 3.5, still more preferably 2.0 to 3.0 from the
viewpoints of the appearance and molding processability of the
molded article. It should be noted that the relative viscosity as
used herein is a ratio of a falling time (t), which is measured for
a solution obtained by dissolving 1 g of a polyamide in 100 mL of
96% sulfuric acid at 25.degree. C. using a Cannon-Fenske
viscometer, to a falling time (t0), which is measured for 96%
sulfuric acid itself in the same manner as above, and is
represented by the following equation (1). Relative viscosity=t/t0
(1)
The number average molecular weight (Mn) of the polyamide (A),
which is determined by gel permeation chromatography (GPC)
measurement, falls within the range of preferably from 10,000 to
50,000, more preferably from 12,000 to 40,000, still more
preferably from 14,000 to 30,000. When the Mn is adjusted to the
range, the mechanical strength of a molded article obtained from
the polyamide is stabilized, and the polyamide has an appropriate
melt viscosity necessary for satisfactory processability in terms
of moldability.
Meanwhile, the dispersivity (weight average molecular weight/number
average molecular weight=Mw/Mn) falls within the range of
preferably from 1.5 to 5.0, more preferably from 1.5 to 3.5. When
the dispersivity is adjusted to the range, fluidity in melting and
stability of the melt viscosity are improved, resulting in
satisfactory processability in melt kneading or melt molding.
Further, the polyamide is satisfactory in toughness as well as some
physical properties such as water absorption resistance, chemical
resistance, and heat aging resistance.
<Organic Halogen Compound (B)>
Examples of the organic halogen compound (B) that serves as a flame
retardant may include brominated polystyrene, brominated
polyphenylene ether, brominated polycarbonate, a brominated
bisphenol-type epoxy-based polymer, a brominated styrene maleic
anhydride polymer, a brominated epoxy resin, a brominated phenoxy
resin, decabromodiphenyl ether, decabromobiphenyl, a brominated
crosslinked aromatic polymer, and perchlorocyclopentadecane. Of
those, a bromine-based compound is preferred, and brominated
polystyrene and brominated polyphenylene ether are particularly
preferred from the viewpoints of flame retardance and thermal
degradation resistance. The compounds may be used alone or in
combination of two or more kinds thereof. A halogen atom content in
the organic halogen compound (B) is preferably 15 to 87% by mass,
more preferably 20 to 60% by mass from the viewpoints of flame
retardance and thermal degradation resistance.
The content of the organic halogen compound (B) is 1 to 100 parts
by mass, preferably 10 to 60 parts by mass with respect to 100
parts by mass of the polyamide (A). If the content of the organic
halogen compound (B) is less than 1 part by mass with respect to
100 parts by mass of the polyamide (A), a flame-retardant effect is
not obtained, while if the content exceeds 100 parts by mass with
respect to 100 parts by mass of the polyamide (A), mechanical
properties are significantly lowered.
<Inorganic Compound (C)>
Examples of the inorganic compound (C) that serves as a flame
retardant aid may include antimony trioxide, antimony pentoxide,
sodium antimonate, tin oxide, iron oxide, zinc oxide, zinc borate,
magnesium hydroxide, calcium hydroxide, calcium carbonate, and
kaolin clay. Of those, antimony trioxide, antimony pentoxide, and
sodium antimonate are preferred from the viewpoints of flame
retardance and thermal decomposition resistance. The compounds may
be treated with, for example, a silane coupler or a titanium
coupler, and may be used alone or in combination of two or more
kinds thereof.
The content of the inorganic compound (C) is 0.5 to 50 parts by
mass, preferably 1 to 30 parts by mass with respect to 100 parts by
mass of the polyamide (A). If the content of the inorganic compound
(C) is less than 0.5 part by mass with respect to 100 parts by mass
of the polyamide (A), the flame-retardant effect is low, while if
the content exceeds 50 parts by mass with respect to 100 parts by
mass of the polyamide (A), mechanical properties are lowered, or
the surface state of the molded article is deteriorated.
<Inorganic Filler (D)>
The flame-retardant polyamide resin composition of the present
invention preferably contains the inorganic filler (D) that serves
as a reinforcement from the viewpoints of mechanical properties and
moldability. Examples of the inorganic filler (D) may include a
glass fiber, glass beads, a carbon fiber, a boron fiber, talc,
mica, silica, silica alumina, alumina, graphite, kaolin, titanium
dioxide, and molybdenum disulfide. Of those, a glass fiber and a
carbon fiber are preferred from the viewpoints of mechanical
strength and moldability. The fillers may be used alone or in
combination of two or more kinds thereof.
The content of the inorganic filler (D) is preferably 0 to 100
parts by mass, more preferably 10 to 100 parts by mass,
particularly preferably 50 to 100 parts by mass with respect to 100
parts by mass of the polyamide (A) from the viewpoint of a balance
between mechanical properties and moldability.
The flame-retardant polyamide resin composition of the present
invention may contain, as a component other than the
above-mentioned components, a hindered phenol-based antioxidant, a
hindered amine-based antioxidant, a thio-based antioxidant, a
colorant, an ultraviolet absorber, a light stabilizer, an antistat,
a plasticizer, a lubricant, and a nucleating agent, if
necessary.
Further, in the polyamide resin composition of the present
invention, a heat-resistant resin may be blended as long as the
effect of the present invention is not impaired. Examples of the
heat-resistant resin which may be blended include heat-resistant
thermoplastic resins such as polyphenylene ether (PPE),
polyphenylene sulfide, modified polyolefin, polyether sulfone
(PES), polyether imide (PEI), and a molten liquid crystal polymer,
and modified products of the resins. In the case where the
polyamide resin composition of the present invention is a resin
composition for a sliding part, from the viewpoints of sliding
property and mechanical properties of a molded article, the
composition preferably contains such thermoplastic resin having a
high melting point.
(Polyphenylene Sulfide)
Polyphenylene sulfide which may be blended in the polyamide resin
composition of the present invention is a polymer having a
structural unit represented by the following general formula (I) at
a concentration of 70 mol % or more, preferably 90 mol % or more in
total structural units.
##STR00001##
Examples of the polyphenylene sulfide which may be blended in the
polyamide resin composition of the present invention may include a
polymer having only the structural unit represented by the general
formula (I) as well as polymers having structural units represented
by the following general formulae (II) to (VI), and the polymer may
include one kind or two or more kinds of the units.
##STR00002##
The polyphenylene sulfide may further include a trifunctional
structural unit represented by the following general formula (VII)
at a concentration of 10 mol % or less in the total structural
units.
##STR00003##
The constituent units represented by the general formulae (I) to
(VII) may each have a substituent such as an alkyl group, a nitro
group, a phenyl group, or an alkoxyl group on its aromatic
ring.
The viscosity of the polyphenylene sulfide which may be blended in
the polyamide resin composition of the present invention, which is
determined using a flow tester under a load of 20 kg at a
temperature of 300.degree. C., preferably falls within the range of
preferably from 100 to 10,000 poise, more preferably from 200 to
5,000 poise, still more preferably from 300 to 3,000 poise. The
polyphenylene sulfide may be prepared by an arbitrary method.
In the polyamide resin composition of the present invention, from
the viewpoint of heat resistance, a mass ratio between the
polyamide (A) and the polyphenylene sulfide is preferably 5:95 to
99.9:0.1, more preferably 5:95 to 95:5, still more preferably 20:80
to 80:20.
(Modified Polyolefin)
As the modified polyolefin, there may be used a product obtained by
modification of a polyolefin with an .alpha.,.beta.-unsaturated
carboxylic acid or an ester or metal salt derivative thereof
through copolymerization, or by graft introduction of, for example,
a carboxylic acid or an acid anhydride to a polyolefin. Specific
examples thereof may include, but not limited to, an
ethylene/propylene copolymer, an ethylene/1-butene copolymer, an
ethylene/4-methyl-1-pentene copolymer, an ethylene/1-hexene
copolymer, an ethylene/1-octene copolymer, an ethylene/1-decene
copolymer, a propylene/ethylene copolymer, a propylene/1-butene
copolymer, a propylene/4-methyl-1-pentene copolymer, a
propylene/1-hexene copolymer, a propylene/1-octene copolymer, a
propylene/1-decene copolymer, a propylene/1-dodecene copolymer, an
ethylene/propylene/1,4-hexadiene copolymer, an
ethylene/propylene/dicyclopentadiene copolymer, an
ethylene/1-butene/1,4-hexadiene copolymer, and an
ethylene/1-butene/5-ethylidene-2-norbornene copolymer.
In the polyamide resin composition of the present invention, from
the viewpoints of mechanical strength, impact resistance, heat
resistance, and the like, the amount of the modified polyolefin
blended is preferably 0.5 to 50 parts by mass, more preferably 1 to
45 parts by mass, still more preferably 5 to 40 parts by mass with
respect to 100 parts by mass of the polyamide (A).
(Molten Liquid Crystal Polymer)
It is preferred that the molten liquid crystal polymer have
property of forming a liquid crystal in a molten phase (that is,
exhibiting optical anisotropy) and have an intrinsic viscosity [n],
which is determined in pentafluorophenol at 60.degree. C., of 0.1
to 5 dl/g.
Typical examples of the molten liquid crystal polymer may include,
but not limited to: a polyester which is substantially formed of an
aromatic hydroxycarboxylic acid unit; a polyester which is
substantially formed of an aromatic hydroxycarboxylic acid unit, an
aromatic dicarboxylic acid unit, and an aromatic diol unit; a
polyester which is substantially formed of an aromatic
hydroxycarboxylic acid unit, an aromatic dicarboxylic acid unit,
and an aliphatic diol unit; a polyester amide which is
substantially formed of an aromatic hydroxycarboxylic acid unit and
an aromatic aminocarboxylic acid unit; a polyester amide which is
substantially formed of an aromatic hydroxycarboxylic acid unit, an
aromatic dicarboxylic acid unit, and an aromatic diamine unit; a
polyester amide which is substantially formed of an aromatic
hydroxycarboxylic acid unit, an aromatic aminocarboxylic acid unit,
an aromatic dicarboxylic acid unit, and an aromatic diol unit; and
a polyester amide which is substantially formed of an aromatic
hydroxycarboxylic acid unit, an aromatic aminocarboxylic acid unit,
an aromatic dicarboxylic acid unit, and an aliphatic diol unit.
Examples of the aromatic hydroxycarboxylic acid unit for
constructing the molten liquid crystal polymer may include units
derived from p-hydroxybenzoic acid, m-hydroxybenzoic acid,
6-hydroxy-2-naphthoic acid, 7-hydroxy-2-naphthoic acid, and the
like.
Examples of the aromatic dicarboxylic acid unit may include units
derived from terephthalic acid, isophthalic acid, chlorobenzoic
acid, 4,4'-biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic
acid, 2,7-naphthalenedicarboxylic acid, 4,4'-oxydibenzoic acid,
diphenylmethane-4,4'-dicarboxylic acid,
diphenylsulfone-4,4'-dicarboxylic acid, and the like.
Examples of the aromatic diol acid unit may include units derived
from hydroquinone, resorcinol, methylhydroquinone,
chlorohydroquinone, phenylhydroquinone, 4,4'-dihydroxybiphenyl,
2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene,
4,4'-dihydroxybiphenyl ether, 4,4'-dihydroxybiphenylmethane,
4,4'-dihydroxybiphenyl sulfone, and the like.
Examples of the aliphatic diol acid unit may include units derived
from ethylene glycol, propylene glycol, 1,4-butanediol,
1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol,
1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol,
1,12-dodecanediol, and the like.
Examples of the aromatic aminocarboxylic acid unit may include
units derived from p-aminobenzoic acid, m-aminobenzoic acid,
6-amino-2-naphthoic acid, 7-amino-2-naphthoic acid, and the
like.
Examples of the aromatic diamine unit may include units derived
from p-phenylenediamine, m-phenylenediamine, 4,4'-diaminobiphenyl,
2,6-diaminonaphthalene, 2,7-diaminonaphthalene, and the like.
Preferred examples of the molten liquid crystal polymer may
include: a polyester which is formed of a p-hydroxybenzoic acid
unit and a 6-hydroxy-2-naphthoic acid unit; a polyester which is
formed of a p-hydroxybenzoic acid unit, a 4,4'-dihydroxybiphenyl
unit, and a terephthalic acid unit; a polyester which is formed of
a p-hydroxybenzoic acid unit, an ethylene glycol unit, and a
terephthalic acid unit; and a polyester amide which is formed of a
p-hydroxybenzoic acid unit, a 6-hydroxy-2-naphthoic acid unit, and
p-aminobenzoic acid unit.
In the thermoplastic resin composition of the present invention,
from the viewpoints of molding processability, dimensional
stability and chemical resistance of a molded article, and the
like, the amount of the molten liquid crystal polymer blended is
preferably 0.1 to 200 parts by mass, more preferably 0.5 to 150
parts by mass, still more preferably 1 to 100 parts by mass with
respect to 100 parts by mass of the polyamide (A).
A production method for the polyamide resin composition for a
molding material of the present invention is not particularly
limited, and the composition can be produced by: blending
predetermined amounts of the polyamide (A), the organic halogen
compound (B), the inorganic compound (C), and as required, the
inorganic filler (D), another additive, and another resin; and
melt-kneading the mixture. The melt-kneading can be carried out by
a conventionally known method. For example, the melt-kneading may
be carried out by feeding all materials using a mono-screw or
twin-screw extruder, a Banbury mixer, or another device similar to
them from the base of the extruder in one step; or a method
involving: feeding resin components first; and kneading the
components with melting together with a side-fed fibrous
reinforcement may be carried out to produce pellets. Further, the
method may be one which involves pelletizing different kinds of
compound products and blending the resultant pellets, or one which
involves separately blending part of a powder component or a liquid
component.
<Molded Article>
The flame-retardant polyamide resin composition of the present
invention is excellent not only in flame retardance but also in a
variety of physical properties such as moldability, mechanical
properties, heat resistance, chemical resistance, and low water
absorbability, and can be suitably used in a wide range of
applications and conditions as a molding material for electrical
and electronic parts and other products required to have flame
retardance. The flame-retardant polyamide resin composition of the
present invention may be used to produce a molded product having a
desired shape by a known molding method such as injection molding,
blow molding, extrusion molding, compression molding, stretching,
or vacuum molding.
EXAMPLES
Hereinafter, the present invention is described in more detail by
way of Examples and Comparative Examples, but is not limited to the
examples. It should be noted that measurement for a variety of
items in the examples was carried out by the following methods.
(1) Relative Viscosity of Polyamide
1 g of a polyamide was weighed accurately and dissolved in 100 ml
of 96% sulfuric acid with stirring at 20 to 30.degree. C. After the
polyamide was dissolved completely, 5 ml of the solution were
immediately taken to a Canon-Fenske viscometer and allowed to stand
in a thermostat bath at 25.degree. C. for 10 minutes, and then a
falling time (t) was measured. Meanwhile, a falling time (t0) of
96% sulfuric acid itself was measured in the same way as above. A
relative viscosity was calculated from the t and t0 values by the
following equation (1). Relative viscosity=t/t0 (1) (2) YI Value of
Polyamide
In accordance with JIS-K-7105, a YI value was measured by a
reflection method. A polyamide having a higher YI value is
evaluated to be more colored in yellow. As a device for measurement
of the YI value, a color difference measurement device manufactured
by Nippon Denshoku Industries Co., Ltd. (type: Z-.SIGMA.80 Color
Measuring System) was used.
(3) Phosphorus Atom Concentration
A phosphorus atom concentration was measured by a fluorescent X-ray
analysis. As a measurement device, ZSX primus (tradename)
manufactured by Rigaku Corporation was used. The analysis was
carried out under conditions of: vacuum tube: Rh 4 kW; atmosphere:
vacuum; analysis window: polyester film 5 .mu.m; measurement mode:
EZ scan; and measurement diameter: 30 mm.phi.. Calculation was
carried out by SQX calculation using software manufactured by
Rigaku Corporation.
(4) Molecular Weight
A molecular weight was measured by gel permeation chromatography
(GPC). As a measurement device, there was used a GPC device
HLC-8320GPC (tradename) manufactured by TOSOH CORPORATION, to which
were connected two columns TSKgel Super HM-H (tradename)
manufactured by TOSOH CORPORATION as measurement columns. As a
solvent, hexafluoroisopropanol (HFIP) was used, and 10 mg of a
polyamide used as a sample was dissolved in 10 g of HFIP and used
in measurement. Measurement was carried out under conditions of:
column temperature: 40.degree. C.; and solvent flow rate: 0.3
mL/min, and polymethyl methacrylate was used as a standard sample,
to determine a number average molecular weight (Mn) and a weight
average molecular weight (Mw).
(5) Flammability
A burn test was carried out in accordance with a standard of UL94V
shown below. A test piece with a size of 125.times.13.times.6 mm
was fixed vertically using a clamp, and dried absorbent cotton was
placed on the lower side of the test piece. A predetermined flame
was brought into contact with the lower end of the test piece, kept
for 10 seconds in that state, and then taken away from the test
piece, and a burning time (first flame contact) was measured. After
fire extinguishing, a flame was brought into contact with the lower
end of the test piece again for 10 seconds, and a burning time
(second flame contact) was measured. For five test pieces,
measurement was carried out to evaluate the test pieces to be V-0,
V-1, or V-2, selected from the following classification.
TABLE-US-00001 TABLE 1 Flammability classification Judgment
criteria V-0 V-1 V-2 Burning time of each 10 seconds 30 seconds 30
seconds test piece or less or less or less Total burning time of
five 50 seconds 250 seconds 250 seconds test pieces or less or less
or less Red heat time after second 30 seconds 60 seconds 60 seconds
flame contact or less or less or less Burning up to clamp No No No
Ignition of absorbent cotton No No Yes caused by flame-emitting
droplet
(6) Mechanical Properties of Molded Article
Mechanical properties of a molded article were measured under the
following conditions.
TABLE-US-00002 TABLE 2 Test item Test method Test piece dimension
Tensile strength According to ISO527 ISO3167 dumbbell piece Tensile
elastic modulus Same as above Same as above Bending strength
According to ISO178 80 .times. 10 .times. 4 mm Bending elastic
modulus Same as above 80 .times. 10 .times. 4 mm Charpy impact
strength According to ISO179 80 .times. 10 .times. 4 mm
High-temperature bending According to ISO178, 80 .times. 10 .times.
4 mm elastic modulus measured at 140.degree. C. Deflection
temperature According to ISO75 80 .times. 10 .times. 4 mm under
load
(7) Equilibrium Water Absorption
The absolute dry mass of a disk-shaped test piece (diameter 50
mm.times.thickness 3 mm) was weighed, and then the test piece was
dipped in atmospheric boiling water. Changes of the mass were
measured with time, and the water absorption at the time when no
change in the mass was observed was determined as an equilibrium
water absorption.
Synthesis Example 1
8,950 g (44.25 mol) of sebacic acid (manufactured by ITOH OIL
CHEMICALS CO., LTD., tradename: Sebacic Acid TA), 12.54 g (0.073
mol) of calcium hypophosphite (manufactured by KANTO CHEMICAL CO.,
INC.), and 6.45 g (0.073 mol) of sodium acetate (KANTO CHEMICAL
CO., INC.) were weighed accurately and fed to a reaction container
having an inner volume of 50 L and equipped with a stirrer, a
dephlegmator, a cooler, a thermometer, a dropping device, a
nitrogen inlet tube, and a strand die (a molar ratio between a
phosphorus atom in calcium hypophosphite and sodium acetate was
0.5). Air in the reaction container was sufficiently replaced with
nitrogen, and the container was pressurized with nitrogen to 0.3
MPa and heated with stirring to 160.degree. C. to melt sebacic acid
uniformly. Subsequently, 6,026 g (44.25 mol) of p-xylylenediamine
(manufactured by MITSUBISHI GAS CHEMICAL COMPANY, INC.) were added
dropwise with stirring over 170 minutes. During this procedure, the
inner temperature of the reaction container was raised continuously
up to 281.degree. C. In the dropping step, the pressure was
controlled to 0.5 MPa, and generated water was removed to the
outside of the system through the dephlegmator and cooler. The
temperature of the dephlegmator was controlled so as to fall within
the range of from 145 to 147.degree. C. After completion of
dropping of p-xylylenediamine, the pressure was reduced at a rate
of 0.4 MPa/h to ordinary pressure over 60 minutes. During this
procedure, the inner temperature was raised up to 300.degree. C.
After that, the pressure was reduced at a rate of 0.002 MPa/min to
0.08 MPa over 20 minutes. Subsequently, the reaction was continued
at 0.08 MPa until the torque of the stirring device reached a
predetermined value. After that, the system was pressurized with
nitrogen, and a polymer was taken out from the strand die and
pelletized, to thereby obtain about 13 kg of a polyamide (PA1).
Table 3 shows values of physical properties of the resultant
polyamide (PA1). The polyamide (PA1) was found to have a phosphorus
atom concentration of 315 ppm, a YI value of -6.5, a relative
viscosity of 2.47, a number average molecular weight Mn of 21,000,
and an Mw/Mn of 2.6.
Synthesis Example 2
Melt polycondensation was carried out in the same manner as in
Synthesis Example 1 except that the kind and blending amount of the
dicarboxylic acid were changed to 8,329 g (44.25 mol) of azelaic
acid (manufactured by Cognis, tradename: EMEROX 1144), to thereby
obtain a polyamide (PA2).
Table 3 shows values of physical properties of the resultant
polyamide (PA1). The polyamide (PA2) was found to have a phosphorus
atom concentration of 302 ppm, a YI value of -1.0, a relative
viscosity of 2.22, a number average molecular weight Mn of 17,500,
and an Mw/Mn of 2.5.
Synthesis Example 3
Melt polycondensation was carried out in the same manner as in
Synthesis Example 1 except that the diamine component was changed
to 5,423 g (39.82 mol) of p-xylylenediamine (manufactured by
MITSUBISHI GAS CHEMICAL COMPANY, INC.) and 603 g (4.43 mol) of
m-xylylenediamine (manufactured by MITSUBISHI GAS CHEMICAL COMPANY,
INC.) (p-xylylenediamine and m-xylylenediamine accounted for 90 mol
% and 10 mol % of the diamine component, respectively), to thereby
obtain a polyamide (PA3).
Table 3 shows values of physical properties of the resultant
polyamide (PA1). The polyamide (PA3) was found to have a phosphorus
atom concentration of 300 ppm, a YI value of -2.0, a relative
viscosity of 2.11, a number average molecular weight Mn of 17,200,
and an Mw/Mn of 2.7.
Synthesis Example 4
Melt polycondensation was carried out in the same manner as in
Synthesis Example 1 except that the amount of calcium hypophosphite
blended was changed to 1.19 g (0.007 mol), and the amount of sodium
acetate blended was changed to 0.57 g (0.007 mol) (a molar ratio
between a phosphorus atom in calcium hypophosphite and sodium
acetate was 0.5), to thereby obtain a polyamide (PA4). Table 3
shows values of physical properties of the resultant polyamide
(PA4).
The polyamide (PA4) was found to have a phosphorus atom
concentration of 28 ppm, a YI value of 25.0, a relative viscosity
of 2.23, a number average molecular weight Mn of 18,000, and an
Mw/Mn of 2.6.
Synthesis Example 5
Melt polycondensation was carried out in the same manner as in
Synthesis Example 1 except that the amount of calcium hypophosphite
blended was changed to 49.25 g (0.292 mol), and the amount of
sodium acetate blended was changed to 23.95 g (0.292 mol) (a molar
ratio between a phosphorus atom in calcium hypophosphite and sodium
acetate was 0.5). In this case, the molecular weight increased
rapidly during melt polymerization, and it was difficult to control
the molecular weight.
Table 3 shows values of physical properties of the resultant
polyamide (PA5). The polyamide (PA5) was found to have a phosphorus
atom concentration of 1,210 ppm, a YI value of 0.5, a relative
viscosity of 2.42, a number average molecular weight Mn of 40,000,
and an Mw/Mn of 2.7.
TABLE-US-00003 TABLE 3 Phosphorus atom- Polymerization rate
Polyamide containing compound modifier Phosphorus Rela- Number
Dicar- Addition Addition atom tive average boxylic Di- Name of
amount Name of amount concentration YI viscos- molecular acid amine
substance (mol) substance (mol) (ppm) value ity weight Mn Mw/Mn
Synthesis PA1 Sebacic PXDA Calcium 0.073 Sodium 0.073 315 -6.5 2.47
21,000- 2.6 Example 1 acid hypophosphite acetate Synthesis PA2
Azelaic PXDA Calcium 0.073 Sodium 0.073 302 -1.0 2.22 17,500- 2.5
Example 2 acid hypophosphite acetate Synthesis PA3 Sebacic PXDA/
Calcium 0.073 Sodium 0.073 300 -2.0 2.11 17,20- 0 2.7 Example 3
acid MXDA = hypophosphite acetate 90/10 Synthesis PA4 Sebacic PXDA
Calcium 0.007 Sodium 0.007 28 25.0 2.23 18,000 - 2.6 Example 4 acid
hypophosphite acetate Synthesis PA5 Sebacic PXDA Calcium 0.292
Sodium 0.292 1,210 0.5 2.42 40,00- 0 2.7 Example 5 acid
hypophosphite acetate PXDA: p-xylylenediamine MXDA:
m-xylylenediamine
Example 1
30 parts by mass of brominated polystyrene (manufactured by
Nissan-Ferro Organic Chemical Company, Ltd., tradename: PyroChek
68PB, halogen atom content: 66% by mass) and 10 parts by mass of
antimony trioxide (manufactured by Nihon Seiko Co., LTD.,
tradename: Padox C) were dry-blended in 100 parts by mass of the
polyamide (PA1) which had been dried under reduced pressure at
150.degree. C. for 7 hours. The mixture was fed to a base hopper of
a twin-screw extruder (manufactured by TOSHIBA MACHINE CO., LTD.,
tradename: TEM37BS) at a rate of 8 kg/h, and extruded at a cylinder
temperature of 280 to 300.degree. C. and a screw rotation speed of
150 rpm, and side-feeding of 100 parts by mass of a glass fiber
(manufactured by Nippon Electric Glass Co., Ltd., tradename:
03T-296 GH) with respect to 100 parts by mass of the polyamide
(PA1) was carried out, to thereby prepare resin composition
pellets. The resultant resin composition pellets were subjected to
injection molding using an injection molding machine (manufactured
by Sumitomo Heavy Industries, Ltd., tradename: SE130DU-HP) at a
cylinder temperature of 300.degree. C. and a mold temperature of
120.degree. C., to thereby obtain a test piece for evaluation. For
the resultant test piece, physical properties of the molded article
were measured. Table 4 shows the results of the evaluation.
Example 2
A test piece for evaluation was obtained in the same manner as in
Example 1 except that the polyamide (PA1) was changed to the
polyamide (PA2). For the resultant test piece, physical properties
of the molded article were measured. Table 4 shows the results of
the evaluation.
Example 3
A test piece for evaluation was obtained in the same manner as in
Example 1 except that the polyamide (PA1) was changed to the
polyamide (PA3). For the resultant test piece, physical properties
of the molded article were measured. Table 4 shows the results of
the evaluation.
Example 4
A test piece for evaluation was obtained in the same manner as in
Example 1 except that 30 parts by mass of brominated polystyrene
were changed to 80 parts by mass of brominated polyphenylene ether
(manufactured by ALBEMARLE JAPAN CORPORATION, tradename:
SAYTEX102E, halogen atom content: 83% by mass). For the resultant
test piece, physical properties of the molded article were
measured. Table 4 shows the results of the evaluation.
Example 5
A test piece for evaluation was obtained in the same manner as in
Example 4 except that the amount of brominated polyphenylene ether
blended was changed from 80 parts by mass to 4 parts by mass. For
the resultant test piece, physical properties of the molded article
were measured. Table 4 shows the results of the evaluation.
Example 6
A test piece for evaluation was obtained in the same manner as in
Example 1 except that 10 parts by mass of antimony trioxide were
changed to 1 part by mass of antimony pentoxide (manufactured by
NISSAN CHEMICAL INDUSTRIES, LTD., tradename: NA-1030). For the
resultant test piece, physical properties of the molded article
were measured. Table 4 shows the results of the evaluation.
Example 7
A test piece for evaluation was obtained in the same manner as in
Example 6 except that 1 part by mass of antimony trioxide was
changed to 40 part by mass of sodium antimonate. For the resultant
test piece, physical properties of the molded article were
measured. Table 4 shows the results of the evaluation.
Example 8
A test piece for evaluation was obtained in the same manner as in
Example 1 except that the amount of the glass fiber blended was
changed from 100 parts by mass to 50 parts by mass. For the
resultant test piece, physical properties of the molded article
were measured. Table 4 shows the results of the evaluation.
Example 9
A test piece for evaluation was obtained in the same manner as in
Example 8 except that the glass fiber was changed to a PAN-based
chopped carbon fiber. For the resultant test piece, physical
properties of the molded article were measured. Table 4 shows the
results of the evaluation.
Example 10
A test piece for evaluation was obtained in the same manner as in
Example 1 except that the glass fiber was not blended. For the
resultant test piece, physical properties of the molded article
were measured. Table 4 shows the results of the evaluation.
Example 11
A test piece for evaluation was obtained in the same manner as in
Example 1 except that the amount of brominated polyphenylene
blended was changed from 30 parts by mass to 10 parts by mass, and
the amount of antimony trioxide blended was changed from 10 parts
by mass to 4 parts by mass. For the resultant test piece, physical
properties of the molded article were measured. Table 4 shows the
results of the evaluation.
Comparative Example 1
30 parts by mass of brominated polystyrene (manufactured by
Nissan-Ferro Organic Chemical Company, Ltd., tradename: PyroChek
66PB) and 10 parts by mass of antimony trioxide (manufactured by
Nihon Seiko Co., LTD., tradename: Padox C) were dry-blended in 100
parts by mass of a polyamide 6T (polyhexamethylene terephthalamide,
manufactured by Solvay, tradename: Amodel). The mixture was fed to
a base hopper of a twin-screw extruder (manufactured by TOSHIBA
MACHINE CO., LTD., tradename: TEM37BS) at a rate of 8 kg/h, and
extruded at a cylinder temperature of 300 to 340.degree. C. and a
screw rotation speed of 150 rpm, and side-feeding of 100 parts by
mass of a glass fiber (manufactured by Nippon Electric Glass Co.,
Ltd., tradename: 03T-296GH) with respect to 100 parts by mass of
the resin was carried out, to thereby prepare resin composition
pellets. The resultant resin composition pellets were subjected to
injection molding using an injection molding machine (manufactured
by Sumitomo Heavy Industries, Ltd., tradename: SE130DU-HP) at a
cylinder temperature of 340.degree. C. and a mold temperature of
130.degree. C., to thereby obtain a test piece for evaluation. For
the resultant test piece, physical properties of the molded article
were measured. Table 4 shows the results of the evaluation.
Comparative Example 2
30 parts by mass of brominated polystyrene (manufactured by
Nissan-Ferro Organic Chemical Company, Ltd., tradename: PyroChek
66PB) and 10 parts by mass of antimony trioxide (manufactured by
Nihon Seiko Co., LTD., tradename: Padox C) were dry-blended in 100
parts by mass of a polyamide 46 (polytetramethylene adipamide,
manufactured by DSM, tradename: Stanyl). The mixture was fed to a
base hopper of a twin-screw extruder (manufactured by TOSHIBA
MACHINE CO., LTD., tradename: TEM37BS) at a rate of 8 kg/h, and
extruded at a cylinder temperature of 290 to 310.degree. C. and a
screw rotation speed of 150 rpm, and side-feeding of 100 parts by
mass of a glass fiber (manufactured by Nippon Electric Glass Co.,
Ltd., tradename: 03T-296GH) with respect to 100 parts by mass of
the resin was carried out, to thereby prepare resin composition
pellets. The resultant resin composition pellets were subjected to
injection molding using an injection molding machine (manufactured
by Sumitomo Heavy Industries, Ltd., tradename: SE130DU-HP) at a
cylinder temperature of 310.degree. C. and a mold temperature of
120.degree. C., to thereby obtain a test piece for evaluation. For
the resultant test piece, physical properties of the molded article
were measured. Table 4 shows the results of the evaluation.
Comparative Example 3
A test piece for evaluation was obtained in the same manner as in
Example 1 except that the polyamide (PA1) was changed to the
polyamide (PA4). For the resultant test piece, physical properties
of the molded article were measured. Table 4 shows the results of
the evaluation.
Comparative Example 4
A test piece for evaluation was obtained in the same manner as in
Example 1 except that the polyamide (PA1) was changed to the
polyamide (PA5). For the resultant test piece, physical properties
of the molded article were measured. Table 4 shows the results of
the evaluation.
Comparative Example 5
A test piece for evaluation was obtained in the same manner as in
Example 1 except that brominated polystyrene was not blended. For
the resultant test piece, physical properties of the molded article
were measured. Table 4 shows the results of the evaluation.
Comparative Example 6
A test piece for evaluation was obtained in the same manner as in
Example 1 except that brominated polystyrene and antimony trioxide
were not blended. For the resultant test piece, physical properties
of the molded article were measured. Table 4 shows the results of
the evaluation.
Comparative Example 7
A test piece for evaluation was obtained in the same manner as in
Example 1 except that the amount of brominated polyphenylene
blended was changed from 30 parts by mass to 150 parts by mass. For
the resultant test piece, physical properties of the molded article
were measured. Table 4 shows the results of the evaluation.
Comparative Example 8
A test piece for evaluation was obtained in the same manner as in
Example 1 except that antimony trioxide was not blended. For the
resultant test piece, physical properties of the molded article
were measured. Table 4 shows the results of the evaluation.
Comparative Example 9
A test piece for evaluation was obtained in the same manner as in
Example 1 except that the amount of antimony trioxide blended was
changed from 10 parts by mass to 70 parts by mass. For the
resultant test piece, physical properties of the molded article
were measured. Table 4 shows the results of the evaluation.
Comparative Example 10
An attempt to prepare resin composition pellets was made in the
same manner as in Example 1 except that the amount of the glass
fiber blended was changed from 100 parts by mass to 250 parts by
mass. However, it was impossible to prepare the resin composition
pellets because fuzzy strands were formed.
TABLE-US-00004 TABLE 4 Example 1 2 3 4 5 Polyamide (A) PA1 PA2 PA3
PA1 PA1 (parts by mass) 100 100 100 100 100 Organic halogen
Brominated 30 30 30 -- -- compound (B) polystyrene (parts by mass)
Brominated -- -- -- 80 4 polyphenylene ether Inorganic Antimony 10
10 10 10 10 compound (C) trioxide (parts by mass) Antimony -- -- --
-- -- pentoxide Sodium -- -- -- -- -- antimonate Inorganic Glass
fiber 100 100 100 100 100 filler (D) Carbon fiber -- -- -- -- --
(parts by mass) Flame retardance V-0 V-0 V-0 V-0 V-1 Physical
properties of molded article Tensile strength (MPa) 219 212 209 186
248 Tensile elastic modulus (GPa) 17.6 17.2 17.5 15.2 18 Bending
strength (MPa) 364 336 311 321 372 Bending elastic modulus (GPa)
14.7 14.5 14.3 12.8 15.2 Charpy impact strength (kJ/m.sup.2) 14.3
13 16 12.1 14.8 High-temperature bending 9.4 9.1 8.6 8.2 9.6
elastic modulus (GPa) Deflection temperature under 272 269 262 268
270 load (.degree. C.) Equilibrium water absorption 1.5 1.6 1.4 1.5
1.5 (% by mass) Example 6 7 8 9 10 11 Polyamide (A) PA1 PA1 PA1 PA1
PA1 PA1 (parts by mass) 100 100 100 100 100 100 Organic halogen
Brominated 30 30 30 30 30 10 compound (B) polystyrene (parts by
mass) Brominated -- -- -- -- -- -- polyphenylene ether Inorganic
Antimony -- -- 10 10 10 4 compound (C) trioxide (parts by mass)
Antimony 1 -- -- -- -- -- pentoxide Sodium -- 40 -- -- -- --
antimonate Inorganic Glass fiber 100 100 50 -- -- 100 filler (D)
Carbon fiber -- -- -- 50 -- -- (parts by mass) Flame retardance V-1
V-0 V-0 V-0 V-1 V-0 Physical properties of molded article Tensile
strength (MPa) 226 195 146 330 70 239 Tensile elastic modulus (GPa)
17.8 15.8 10.5 25.9 3 18.3 Bending strength (MPa) 368 336 239 384
117 370 Bending elastic modulus (GPa) 14.6 13.1 9.1 21 2.1 15.2
Charpy impact strength (kJ/m.sup.2) 14.2 12.8 28.1 27.9 50 16
High-temperature bending 9.4 8.6 -- -- -- 9.5 elastic modulus (GPa)
Deflection temperature under 272 270 253 258 221 272 load (.degree.
C.) Equilibrium water absorption 1.4 1.5 1.8 1.8 2.8 1.5 (% by
mass) Comparative Example 1 2 3 4 5 Polyamide (A) PA6T PA46 PA4 PA5
PA1 (parts by mass) 100 100 100 100 100 Organic halogen Brominated
30 30 30 30 -- compound (B) polystyrene (parts by mass) Brominated
-- -- -- -- -- polyphenylene ether Inorganic Antimony 10 10 10 10
10 compound (C) trioxide (parts by mass) Antimony -- -- -- -- --
pentoxide Sodium -- -- -- -- -- antimonate Inorganic Glass fiber
100 100 100 100 100 filler (D) Carbon fiber -- -- -- -- -- (parts
by mass) Flame retardance V-0 V-0 V-0 V-0 V-2 Physical properties
of molded article Tensile strength (MPa) 129 146 210 205 237
Tensile elastic modulus (GPa) 16.5 160.4 17.5 16 18 Bending
strength (MPa) 210 201 352 354 380 Bending elastic modulus (GPa)
14.4 12 15.5 15.4 15.1 Charpy impact strength (kJ/m.sup.2) 10.1
11.4 13.5 14.4 17.2 High-temperature bending 7.2 8.1 9.3 9.2 9.6
elastic modulus (GPa) Deflection temperature under 263 289 271 272
272 load (.degree. C.) Equilibrium water absorption 3.4 3.6 1.5 1.4
1.5 (% by mass) Comparative Example 6 7 8 9 10 Polyamide (A) PA1
PA1 PA1 PA1 PA1 (parts by mass) 100 100 100 100 100 Organic halogen
Brominated -- 150 30 30 30 compound (B) polystyrene (parts by mass)
Brominated -- -- -- -- -- polyphenylene ether Inorganic Antimony --
10 -- 70 10 compound (C) trioxide (parts by mass) Antimony -- -- --
-- -- pentoxide Sodium -- -- -- -- -- antimonate Inorganic Glass
fiber 100 100 100 100 250 filler (D) Carbon fiber -- -- -- -- --
(parts by mass) Flame retardance V-2 V-0 V-1 V-0 -- Physical
properties of molded article Tensile strength (MPa) 259 92 223 123
It was Tensile elastic modulus (GPa) 18.5 9.1 17.9 14.2 impossible
Bending strength (MPa) 394 260 370 280 to prepare Bending elastic
modulus (GPa) 16.2 11.9 15.2 12.5 pellets Charpy impact strength
(kJ/m.sup.2) 19 6.2 15.1 7.1 because of High-temperature bending
10.4 3.2 9.7 3.8 fuzzy elastic modulus (GPa) strands. Deflection
temperature under 272 248 271 265 load (.degree. C.) Equilibrium
water absorption 0.2 1.4 1.5 1.5 (% by mass) PA6T:
polyhexamethylene terephthalamide PA46: polytetramethylene
adipamide
It should be noted that, in Examples 8 to 10, the high-temperature
bending elastic moduli were not measured.
As clear from Table 4, each of the molded articles of Comparative
Examples 1 and 2 using the polyamide 6T or the polyamide 46 was
found to have low mechanical strength and a low elastic modulus and
had high equilibrium water absorption. A nylon 46 resin, which has
conventionally been studied as a resin for an electronic part, is a
resin obtained from tetramethylenediamine and adipic acid, and is
excellent in heat resistance and mechanical properties. However,
the resin contains an amide group at a higher ratio compared with
usual polyamide resins such as a nylon 6 resin and a nylon 66 resin
and hence has the drawback of high water absorption. Therefore,
although the nylon 46 resin has excellent heat resistance and
mechanical properties in a dry state, in actual use, the resin has
a higher water absorption compared with usual polyamide resins and
hence shows larger reductions in heat resistance and mechanical
properties compared with the usual resins. Further, the high water
absorption leads to a large change in dimension accordingly, and
hence the dimensional accuracy is insufficient in some cases.
Therefore, it is difficult to use the resin in parts required to
have high accuracy. Moreover, due to a water absorption state, in
mounting on a substrate in a surface mounting system, damage called
blister appears on the surface of a part, resulting in
significantly lowered performance and reliability of the part.
The polyamide (PA4) having a phosphorus atom concentration of 50
ppm or less has a large YI value, and hence the molded article
obtained from the polyamide has a yellowish color and has a lowered
commercial value (Comparative Example 3). Meanwhile, in the case of
the polyamide (PA5) having a phosphorus atom concentration of 1,000
ppm or more, the molecular weight increased significantly during
melt polymerization, and it was impossible to control the molecular
weight (Comparative Example 4).
Further, each of the molded articles of Comparative Examples 5 and
6, in which no organic halogen compound (B) serving as a flame
retardant was blended, was found to have low flame retardance. In
addition, the molded article of Comparative Example 7, to which an
excessive amount of the organic halogen compound (B) serving as a
flame retardant was added, and the molded article of Comparative
Example 9, to which an excessive amount of the inorganic compound
(C) serving as a flame retardant aid was added, were found to be
poor in mechanical properties.
The molded article of Comparative Example 8, to which no inorganic
compound (C) serving as a flame retardant aid was added, was found
to be poor in flame retardance compared with the molded article of
Example 1.
Further, in the case of the resin composition to which an excessive
amount of the inorganic filler (D) was added, fuzzy strands were
produced in pelletization, and hence it was impossible to produce
pellets (Comparative Example 10).
Meanwhile, in the case of each of the polyamide (PA1) to polyamide
(PA3) used in Examples 1 to 11, the molecular weight was able to be
controlled in melt polymerization. Further, the resultant resin was
hardly colored, and the molded article formed was found to have
excellent appearance. In addition, each of the molded articles of
Examples 1 to 11 obtained by using the polyamide resins was found
to have low water absorption and to be excellent in flame
retardance, mechanical properties, and heat resistance.
Industrial Applicability
The flame-retardant polyamide resin composition of the present
invention is excellent not only in flame retardance but also in a
variety of physical properties such as moldability, mechanical
properties, heat resistance, and low water absorbability, and can
be suitably used in a wide range of applications and conditions as
a molding material for a variety of industries and industrial and
household products such as electrical and electronic parts,
automotive parts, and mechanical parts required to have flame
retardance.
* * * * *